The present invention relates to a method for producing peracetic acid by reacting hydrogen peroxide and acetic acid in a aqueous reaction medium, from which peracetic acid is continuously distilled off.
Peracetic acid in aqueous solution can be used as disinfectant or for bleaching various materials and is especially suited for environment-friendly bleaching of cellulose pulp. Prior-art production processes, however, are not sufficiently efficient to be of commercial interest.
GB Patent 949,094 discloses the production of peracetic acid by distilling off peracetic acid from a reaction medium containing acetic acid, hydrogen peroxide, peracetic acid and sulphuric acid in equilibrium. However, the described process has a production rate of only about 1 g peracetic acid per kg reaction medium and minute.
D. Swern, "Organic Peroxides", Vol. 1, John Wiley & Sons, New York 1970, pp 349-351, describes a similar process, but mentions no production rates.
The present invention concerns a solution to the problem of providing an efficient process for producing peracetic acid from acetic acid and hydrogen peroxide in aqueous phase, the product preferably containing as little impurities as possible, for instance of acetic acid. Since peracetic acid easily decomposes, both safety problems and high investment costs for the process equipment will arise for large volumes of reaction medium, and therefore it is desirable to achieve a high production rate in relation to the amount of reaction medium.